Collector head



June 13, 1967 c. H. WARD 3,325,764

COLLECTOR HEAD Filed Feb. 9, 1965 2 Sheets-Sheet l INVENTOR 6/9/7750 ,6.Ward C H. WARD COLLECTOR HEAD June 13, 1967 2 Sheets-Sheet 2 Filed Feb.9, 1965 INVENTOR Q C/emson /7( WEI/"0 United States Patent 3,325,764COLLECTOR HEAD Clemson H. Ward, Linthicum, Md., assignor to BethlehemSteel Corporation, a corporation of Delaware Filed Feb. 9, 1965, Ser.No. 431,265 10 Claims. (Cl. 3395) This invention relates to a collectorhead assembly, and more particularly to an assembly adapted for use inthe continuous electrolyzin g of metal strip.

In electrolyzing metal strip, and especially in the electrolyticdeposition of a non-ferrous coating on steel strip, the strip may passthrough an electrolytic plating cell in either a horizontal or verticaldirection. An electrode, connected to a source of electric current, isdisposed in the electrolyte in the plating cell in close proximity tothe path of the strip through the electrolyte. A rotatable contact rollengages the strip outside the cell, and the roll is connected to theopposite pole of the electric source to complete the electric circuitthrough a portion of the strip.

In the horizontal type of plating, there are generally a plurality ofplating cells, with the moving strip normally contacting a contact rollat the exit end of each cell. Commonly, the strip passes between tworolls, with a metal, usually steel, contact roll at the top, and abacking roll, covered with some non-conductive substance such as rubber,bearing on the strip immediately below the contact roll.

In the vertical or skein type of plating cell, wherein the strip mayengage a contact roll outside the cell after each vertical pass aroundan electrode disposed vertically in the plating bath, virtually the sametype of roll structure is used as in the horizontal type of operation,except that, in the vertical type, the emerging strip is usually carriedout of the plating bath on a driven contact roll, and is forced intointimate contact therewith by a rubber-coated wringer roll placed abovethe contact roll.

The contact rolls, which are generally made in the form of a hollowcylinder, may vary in diameter, depending on the type of operation, frompossibly 3 inches to 15 inches or more. In a modern, high speedtinplating line of the horizontal type, the roll will have a diameter ofabout inches, and a length sufiicient to take care of at least a 36inch-wide strip. Each end of the roll has a reduceddiameter portion toform a journal which fits within a journal bearing.

Heretofore, it has been the practice to collect current from the contactroll by means of a reduced end portion of the roll. This reduced endportion extend beyond the journaled portion of the roll, and thusprovides ready access for the collector head assembly, of which thebrushes are a part.

Brushes provided relatively satisfactory operation for tin linesoperating at speeds of from 500 to 600 feet per minute. However, withpresent day lines operating at speeds of up to 1500 feet or more perminute, a serious torque problem develops through the use of the brushtype current collector. Even at the slower speeds of around 500 to 600feet per minute, at which speed some tin lines are still operated, theamount of torque drag resulting from the use of brushes is considerable.Power losses increase with increased speed, and at 1500 feet per minutepower loss from drag torque is such that synchronization of roll speedto strip becomes a problem.

An object of this invention is to provide a collector head whichgenerates a minimum of torque on an electroplating contact roll.

Another object is to provide a liquid cooled collector head which can bereadily removed or replaced when not in operation.

A further object is to provide means for maintaining the correct tensionon the contact elements of a collector head, and for changing suchtension as necessary.

Another object is to provide a collector head which is self-supporting,and which follows any change in contact roll alignment.

With these objects in mind, I have developed a lightweight,liquid-cooled collector head having braid-type contact portions, inwhich the tension on the contact portions can be adjusted withoutremoval of the head, and the whole assembly can be removed from itsoperating position, or replaced therein, with a minimum of delay.

In the drawings:

FIG. 1 is a vertical section of the complete assembly taken along theline 11 of FIG. 2.

FIG. 2 is an end view of the assembly, part of which is in section takenalong the line 2-2 of FIG. 1.

FIG. 3 is an end view showing tensioning means.

FIG. 4 is a plan view of a contact drum and one contact braid.

FIG. 5 is an end view of the tension rings, braid and contact drum.

The improved collector head includes a contact plate, which is madeintegral with part of the collector head housing. Within the housing,and attached at one end to the contact plate, is a series of elongatedelectrically conducting contact members of soft material arrangedlongitudinally around the periphery of an electrically conducting,rotating drum. The opposite ends of these elongated contact members arefastened to rotatable tensioning discs, or rings. The drum is connectedboth mechanically and electrically to the end portion of a contact roll,or other electrically conducting, rotating element. The housing is ofclosed construction so as to permit containment and circulation ofcooling liquid in the vicinity of the contact members and the contactdrum. At the free end of the drum, there is located spring-mounted meansfor adjusting tension on the tensioning rings. The rings, in turn,supply tension to the contact members.

The improvement of this invention will be readily understood byreference to the drawings. Referring particularly to FIG. 1, steelcontact roll 10 has a tapered, reduced end portion 11 in metal-to-metalfit with, and bolted at 14 to, brass roll flange 12. Flange 12 is inturn attached to brass collector head flange 13 by means of six boltsindicated at 16. An aluminum bronze contact drum 15 is secured to flange13 by means of six bolts indicated at 17.

In the structure just described, good conductivity is obtained for thepassage of electrical current from the contact roll through successivejoints to the contact drum. However, because of the relatively smallcontact area between drum 15 and flange 13, conductivity may be enhancedif the contact portions of drum and flange are tinned and sweatedtogether.

As an alternative to joining the parts by sweating, conductivity betweendrum 15 and flange 13 could also be enhanced by constructing the drumand flange in one piece.

The brass collector head casing 18 is an integral part of contact plate19. Actual removal of current from drum 15 is performed by a series ofeight strips 20 which can be, for example, 1% inch wide, ,5, inch thick,and of a soft electrically conductive material ofcopper contact braidhaving a contact length of, for example, about four inches. One end ofeach braid is secured physically and electrically to brass contact plate19 by means of brass clamping ring 21 and bolts 22. The other end ofeach braid is secured between two ten-sioning rings 23 and 24, the tworings being held together by stainless steel cap screw 62. The braidsare arrayed longitudinally, and in spaced relation, around the peripheryof contact drum 15.

Current removed from the drum by means of the braid passes through thecontact plate to bus bars, not shown, whence it travels through thegenerators, anodes, electrolyte and strip, as will be understood, tocontact roll to complete the circuit.

The installation of the braid, as described, will normally place thebraid strip in a line parallel with the center line of drum 15, and inclose contact with the surface of said drum throughout the length of theexposed section of the braid. The braid is thus depicted in FIGURE 1.

The braids must be placed under sufficient wrapping tension to ensuregood contact between braid and drum. Tension is maintained by a constantrotative force applied to brass tension rings 23 and 24 by five tensionsprings 48. The torque applied to rings 23 and 24 causes spiral wrappingof the braid around the drum, and is supplied in a direction counter tothe operational rotation of the drum. The spring load is set to about 75to 100 inch pounds, in'a manner which will be described.

Alternatively, the braids may be prestressed in a spiral configurationso that when they are attached to rings 23 and 24 and to ring 21, theywill have already assumed the approximate contour in which they are usedin operation. Inserting the braids in a direction away from the axis ofthe drum, in a prestressed condition, will improve wear of both drum andbraid.

Completing the collector head housing is a brass casing cap 25, joinedto casing 18 by bolts indicated at 26. By this union, the housingprovides a closed container, except for water inlets and outletsdescribed below, for the circulation of cooling Water about drum andbraids 20.

Contact drum 15, which, in this example, rotates in a counter-clockwisedirection in concert with contact roll 10, has a cylindrical opening atthe free end in which it supports a steel shaft 29. The shaft isattached to casing cap 25 by bolts 30. Bearing support for shaft 29within drum 15 is provided by roller bearing housing 31. An

insulating Bakelite bushing 32 is inserted between shaft 29 and bearing31, while Bakelite washers 33 prevent lateral movement of the bearing,the complete bearing assembly being secured to the shaft by steelretaining nut 34. A brass seal and bearing retainer ring .35, secured todrum 15 at 36, carries a rubber seal 37 to prevent water from enteringball race housing 31.

Ball bearing housing 38 provides additional support for the collectorhead casing, housing 38 being retained in place between casing section18 and drum 15 by Bakelite bushing 39 and 39, as well as Bakeliteinsulating bushing 60. Rubber seals 40 and 41 are provided to retaincooling water within the collector head housing proper. Seals 40 and 37also confine lubricating grease within the area occupied by thebearings.

Referring now to FIG. 2, inlets 27 and outlet 28 provide for thecirculation of cooling water about the elements of the collector head,the water entering the housing at inlet nozzle 27. Water within thehousing will be made to circulate about the exposed sides of the braidsand exposed areas of the outside drum surface. Water acts as bothcoolant and lubricant, and as such increases the useful life of both thebraids and the drum. The casing being provided with seals 40' and 41,forms a water-tight compartment for the lubrication and cooling ofbraids and drum. Further to prevent leakage of water from the casing, Oring gasket 42 is located between spring tension and sealing ring 43 andcasing section 25.

Additional means are provided to prevent leakage of water into thebearing areas by inclusion of drain slots 44 and 45.

An inspection hole 46, fitted with a transparent cover 63, is located atthe top of the housing in casing section 18. An air vent 64 is alsolocated at the top of casing section 18.

It will be seen that the entire collector head housing assemblycomprising contact plate 19, casing sections 18 and 25, and allstructures attached thereto, are supported on drum 15 by tightly fittingbearing housings 31 and 38. The assembly is held stationary by means ofheavy wire connections 47 attached to contact plate 19. Theselfsupporting feature of the collector head is important, in that thisfeature permits the head to accommodate to any change in alignment ofthe contact roll, the head thus being in constant alignment with saidroll.

Casing cap 25 is provided with a threaded stud 61 for the purpose ofpushing the cap away from the assembly, when it is desired to remove thecap therefrom.

Proper tension on braids 20 is maintained through the agency of aspring-mounted system which controls the degree of rotation of braidtension rings 23 and 24. With the right end of each braid 20, as shownin FIG. 1, secured between rings 23 and 24, the rings are urgedsimultaneously in a clockwise direction, and counter to the direction ofrotation of drum 15. Freedom of movement of the rings'is provided byTeflon thrust pad 57. Thrust pad 57 bears against bearing spacer sleeve51, which in turn is seated in casing section 18. The degree of rotationof the rings is limited by the braid tension required to maintain asatisfactory electrical contact between braid and drum.

A series of five bronze wire springs 48 is located between tension ring24 and brass spring tension and sealing ring 43. Referring to theuppermost spring 48 in FIG. 1, one end of spring 48 is attached to bolt49, the bolt in turn being secured to ring 24. The other end of spring48 is attached to bolt 49 which is in turn secured to ring 43. Whenclockwise rotational motion is applied to ring 43 by external force, aswill be described, tension is applied to each of the springs 48. Theload applied to the spring moves ring 24, along with its companion ring23, in the same rotational direction as ring 43. As previouslymentioned, braid tension for the apparatus described in this example ismaintained by applying a load of between about 75 and inch pounds to thesprings 48.

Spanner-engaging pins 52, secured to ring 43, extend through slots 53located in casing cap 25, as shown in FIGURES 2 and 3. By applying thespanner 54 of a torque wrench 55 to two diametrically opposed engagingpins 52, as shown in FIG. 3, ring 43 may be rotated to subject springs48 to sufficient tension to in turn rotate tension rings 23 and 24. Whenthe proper tension has been applied to the braids, lock nut 56,operating in slot 53, is tightened, so that the desired load can bemaintained on the braids indefinitely.

As the right end of braid 20 in FIG. 1 is gripped between tension rings23 and 24, any rotation of the rings extends the braid, and tends topull it in a line diagonal to the axis of drum 15. The course taken bythe extended braid, in relation to the drum axis, is shown in FIG. 4.The diagonal pull put on the braid by rotation of drums 23 and 24 willproduce torsion in the braid, although the braid tends to assumesubstantially the contour of the contact drum against which it is held.

The helical direction taken by the braid and the manner by which thebraid is held in position by the tension rings, is clearly shown inFIGS. 4 and 5. A plug fits into a drilled one inch hole 50 at the bottomof casing 18. When the plug is removed, the opening acts as a drainslot. By backwashing with water through outlet 28, the interior of theassembly can be washed to remove fine particles of copper-bearing powderdislodged from the braids and drum. Washing results in a sludge at thebottom of the clasing, which sludge can be removed through the drain 5ot.

The collector head of the example is designed to operate at 4500amperes. By increasing the size of the head a corresponding increase incurrent capacity can be obtained. Ordinarily, in a tinplating line, acollector head will be located at each end of the contact roll.

Obvious substitutions can be made in the choice of materials for thevarious parts of the apparatus described. For the most effectiveoperation, however, all parts of the assembly which aid in the transferof current should be made of a material of high electrical conductivitysuch as copper or the various brasses and bronzes. Silver-plated coppersurfaces, such as those of braid wires, may be found advantageous inovercoming reduced conductivity due to surface corrosion.

The copper braid may be any commercial braid made from copper orcopper-bearing wire of small diameter. Preferably, the braid should bemade from wires having a diameter of approximately 0.010 inch, toproduce optimum flexibility and wear in conjunction with a contact drumof convenient size, e.g. about 3 inches in diameter. The most desirablebraid wire diameter will be dependent to some extent on the diameter ofthe contact drum.

The contact drum, which, in the examples given, has a diameter of about3 inches, and length of inches, may be made from a bronze alloy of thenature of beryllium bronze or aluminum bronze, or from any highlyelectrically conductive metal having a surface hardness suflicient towithstand the wear to which it is subjected. Mill tests have shown thatan aluminum bronze drum-in one instance a drum having a composition ofapproximately 7.5% aluminum, 2% silicon and the remainder copperwillhave a drum wear life of about three to four times that of a drum madefrom beryllium bronze. Aside from improved wear of the drum itself, whenan aluminum bronze drum has been used for a period of 600 hours, only ascattered few wires of the contact braid are cut during the life of thedrum. When beryllium bronze has been used as the drum material, neralyhalf of the contact braid wires have been cut through when in use for amuch shorter operating period.

The reason for the great improvement with the aluminum bronze materialis not clear, but it is believed that it may be due to formation on thedrum surface of a protective aluminum oxide film which is electricallyconductive, as Well as wear-resistant and non-galling when runningagainst copper braid wires.

The apparatus described herein comprises a lightweight assembly, whichcan be readily removed or replaced when contact roll changes arenecessary, or when replacement parts to the assembly itself arerequired. Damage to parts during removal or replacement of the assemblyis substantially completely obviated. Moreover, the assembly provides aself-supporting device of high electrical efiiciency and low dragtorque.

The invention is not limited to electroplating, but can be applied toany electrical operation where current is collected from a rotatingconductive member of cylindrical configuration.

I claim:

1. In a liquid cooled current collecting device, the combination whichcomprises a contact drum secured at one end to a rotary contact member,a housing enclosing said drum, a contact plate attached to said housingand a plurality of pliable contact sections secured at one end to saidcontact plate and aligned in a helical configuration around theperiphery of, and in contact with, said drum, a rotatable ring mountedin said housing and securing the other end of said contact sections,means to maintain torque on said ring, and means for changing the degreeof torque on said ring.

2. In a liquid cooled current collecting device, the combination whichcomprises a contact drum secured at one end to a rotary contact member,a housing enclosing said drum, a contact plate attached to said housingand a plurality of pliable contact sections secured at one end to saidcontact plate and aligned in a helical configuration around theperiphery of, and in contact with, said drum, dual rotatable ringsmounted in said housing and securing the other end of said contactsections, means to maintain torque on said rings, and means for changingthe degree of torque on said rings.

3. In a liquid cooled current collecting device, the combination whichcomprises a metal contact drum secured at one end to a rotary contactmember, a metal 6 housing enclosing said drum and supported on saiddrum, a metal contact plate attached to said housing and a plurality ofpliable metal contact sections secured at one end to said contact plateand aligned in a helical configuration around the periphery of, and incontact with, said drum, a rotatable ring mounted in said housing andsecuring the other end of said contact sections, means to maintaintorque on said ring, and means for changing the degree of torque on saidring.

4. In a liquid cooled current collecting device, the combination whichcomprises a metal contact drum secured at one end to a rotary contactmember, a metal housing enclosing said drum and supported on said drum,a metal contact plate attached to said housing and a plurality ofpliable metal contact sections secured at one end to said contact plateand aligned in a helical configuration around the periphery of and incontact with, said drum, dual rotatable rings mounted in said housingand securing the other end of said contact sections, means to maintaintorque on said rings, and means for changing the degree of torque onsaid rings.

5. In a liquid cooled current collecting device, the combination whichcomprises a metal contact drum se cured at one end to a rotary contactmember, a metal housing enclosing said drum and supported on said drum,a metal contact plate attached to said housing and a plurality ofmetallic braids secured at one end to said contact plate and aligned ina helical configuration around the periphery of, and in contact with,said drum, a rotatable ring mounted in said housing and securing theother end of said contact sections, means to maintain torque on saidring, and means for changing the degree or torque on said ring.

6. In a liquid cooled current collecting device, the combination whichcomprises a bronze contact drum secured at one end to a rotary contactmember, a housing enclosing said drum, a contact plate attached to saidhousing and a plurality of pliable contact sections secured at one endto said contact plate and aligned in a helical configuration around theperiphery of, and in contact with, said drum, a rotatable ring mountedin said housing and securing the other end of said contact sections, aplurality of springs for supplying torque to said ring, a combinationrotatable spring tension and liquid sealing ring for supplying tensionto said springs, and means for securing said spring tension ring infixed position.

7. In a liquid cooled device for collecting current from a rotatablecontact roll, the combination which comprises an aluminum bronze contactdrum secured at one end to said roll, a brass housing enclosing saiddrum and supported thereon, a brass contact plate attached to saidhousing and a plurality of copper wire braid contact sections secured atone end to said contact plate and aligned in a helical configurationaround the periphery of, and in contact with, said drum, dual brassrotatable tension rings mounted in said housing and securing the otherend of said contact sections, a plurality of bronze wire springs forsupplying torque to said rings, a combination rotatable brass springtension and liquid sealing ring for supply ing tension to said springsand means for securing said spring tension ring in fixed position.

8. In a liquid cooled current collecting device, the combination whichcomprises a metal contact drum secured at one end to a rotary contactmember, a metal housing enclosing said drum and supported on said drum,a metal contact plate attached to said housing and a plurality ofpliable metal contact sections secured at one end to said contact plateand aligned in a helical configuration around and in contact with saiddrum, dual rotatable rings mounted in said housing and securing theother end of said contact sections, restraining means to prevent axialmovement of said rings toward said contact plate, and means for applyinga variable and controlled torque on said rings suificient to cause aspiral wrapping of said contact sections about the periphery of saiddrum.

9. A current collecting device comprising a contact drum adapted to besecured at one end to a rotary contact member, a contact plate disposedaround one end of said drum, a rotatable ring disposed about theopposite end of said drum, a plurality of pliable metal contact sectionssecured at one end to said contact plate and secured at the other end tosaid ring, and means for rotating said ring a distance sufiicient toWrap said contact sections in a helical configuration at least partiallyaround the periphery of said drum and in contact with said drum.

10. A current collecting device comprising a contact drum adapted to besecured at one end to a rotary contact member, a contact plate disposedaround said drum at the end nearest said contact member, and in bearingrelation therewith, a rotatable ring disposed about the opposite end ofsaid drum in relation to said contact member and in bearing relationwith said drum, a plurality of pliable metal contact sections secured atone end 8 to said contact plate and secured at the other end to saidring and means for rotating said ring a distance sufficient to Wrap saidcontact sections in a helical configuration at least partially aroundthe periphery of said drum and in contact with said drum.

References Cited UNITED STATES PATENTS 421,320 2/ 1890 Schrnid et al.310-238 1,082,571 12/1913 Varley 310-244 2,438,007 3/1948 Hanna 75-162 X2,583,747 1/1952 Potter 339-5 X 2,773,247 12/1956 Erhardt 339-53,021,497 2/1962 Riley 339-5 3,176,410 4/1965 Klement 75-162 X MARVIN A.CHAMPION, Primary Examiner. A. S. TRASK, Assistant Examiner.

9. A CURRENT COLLECTING DEVICE COMPRISING A CONTACT DRUM ADAPTED TO BESECURED AT ONE END TO A ROTARY CONTACT MEMBER, A CONTACT PLATE DISPOSEDAROUND ONE END OF SAID DRUM, A ROTATABLE RING DISPOSED ABOUT THEOPPOSITE END OF SAID DRUM, A PLURALITY OF PLIABLE METAL CONTACT SECTIONSSECURED AT ONE END TO SAID CONTACT PLATE AND SECURED AT THE OTHER END TOSAID RING, AND MEANS FOR ROTATING SAID RING A DISTANCE SUFFICIENT TOWRAP SAID CONTACT SECTIONS IN A HELICAL CONFIGURATION AT LEAST PARTIALLYAROUND THE PERIPHERY OF SAID DRUM AND IN CONTACT WITH SAID DRUM.